Phosphatase activated crosslinking conjugating and reducing agents; methods of using such agents; and reagents comprising phosphatase activated crosslinking and conjugating agents

A method of crosslinking compounds comprising the steps of:

• (a) activating a compound by deprotecting a thiol group of a phosphothorothioate monoester of said compound, said compound corresponding to the formula (I):
• Q--(S--PO.sub.3.sup.-2).sub.n (I)
• wherein n is at least 1 and Q is a straight or branched monomer, polymer or oligomer having an average molecular weight between about 200 and about 1,000,000 and wherein when n is 1, Q comprises at least 1 additional reactive functionality, and
• (b) contacting said activated compound (I) with at least one compound that is functionalized with at least one electrophilic group and a second group capable of reaction with said activated compound or at least two compounds that are functionalized with at least one electrophilic group, said electrophilic groups selected from the group consisting of heterobifunctional linkers, haloacetyl groups, acrylate groups, quinone groups, epoxide groups, thiopyridyl groups, and transition metal complexes or transition metals in various oxidation states or in colloidal forms, whereby crosslinking is effected creating stabilization of said crosslinked compound.